As mobile communication techniques progress, a home nodeB (HNB) or a home eNodeB (HeNB) to be placed as a smaller access node is introduced as means for configuring a wireless access network in the 3rd Generation Partnership Program (3GPP). Such a smaller access node can expand the service coverage provided to users of the equipment and can provide users with new services at a low cost and at very high speed. Further, conventional utilization form by users of a broadband network also can be diversified and communication resources required by mobile phone operators can be provided at a low cost. This means that the connection via a HNB or a HeNB typically can provide users with decreased cost and additional services.
Access nodes for customer or campus premises introduced allow the 3GPP to further produce a utilization case in a local IP access (LIA or LIPA) disclosed in Non-Patent Document 1 described below, for example. The LIA allows users accessing a closed subscriber group (CSG) cell of the HNB/HeNB to access a core network of an operator as well as a network connected to the HNB/HeNB. This LIA further includes an access to a domestic (home) network or to the Internet without passing through the core network of the operator. A UE is requested to access the LIA and the core network of the operator simultaneously, and the 3GPP further examines a case where a UE is allowed to perform LIA via a macro-cell.
These new utilization cases have the possibility of improving the value of services to be developed in the future, and are effective to perform offloading of a certain amount of traffic from the core network. Conceivably in this case, a conventional operation procedure specified in the following Non-Patent Document 2 can be reused to embody these scenarios.
In the present specification, in order to distinguish home networks (this may be called a HPLMN: Home Public Land Mobile Network) meaning a network of a 3GPP operator having a major contract relationship with a certain UE from home networks meaning a domestic (home) network connected to a certain HNB/HeNB that is viewed from the owner of the network, the former is described as a HPLMN and the latter is described as a LIA domain network.
As a technique relating to the present invention, the invention disclosed in the following Patent Document 1 is known. In the invention disclosed in Patent Document 1, a UE is configured to detect whether a local breakout service is available or not in an IP (Internet Protocol) gateway announced by a base station of the UE. This UE can form an Internet protocol stack to use a local breakout service on the Internet while continuously using a 3GPP service.